I2S pinouts don't match other boards

[thejpster]

The standard VGA demo board (https://shop.pimoroni.com/products/pimoroni-pico-vga-demo-base) uses:

Signal	Pin	GPIO
LRCLK	Pin 34	GPIO28
BCLK	Pin 32	GPIO27
DAT	Pin 31	GPIO26

These docs from Arduino (https://arduino-pico.readthedocs.io/en/stable/i2s.html) note that LRCLK must always be BCLK + 1.

Currently we have:

Signal	Pin	GPIO
BCLK	Pin 34	GPIO28
LRCLK	Pin 32	GPIO27
ADC_DAT	Pin 31	GPIO26
DAC_DAT	Pin 29	GPIO22